The present invention relates to a slide mount for mounting film transparencies from a photographic film web to prepare a photographic slide. In particular, the present invention relates to an improved cardboard slide mount which incorporates a plastic brace between opposing plastic coated cardboard frames.
Photographic film transparencies are generally severed from a photographic film web and are mounted in individual slide mounts to prepare photographic slides. The photographic image of the prepared photographic slide is then viewed in cooperation with a slide projector or other visualizing means.
Slide mounts used in the industry are generally made from either plastic or cardboard. Plastic slide mounts are generally formed of first and second plastic frame portions which are connected along three edges of an outer border to form a pocket therebetween. The plastic slide mounts include a central aperture which is formed by film windows in each of the first and second plastic frame portions. Plastic slide mounts also include a slit along a fourth edge of the outer border. The slit provides an opening through which a photographic film transparency is inserted into the pocket between the first and second frame portions. The fourth edge of the first and second frame portions is easily spaced apart by an opening assembly, which allows an individual film transparency to be quickly and efficiently inserted into the pocket of the slide mount.
Cardboard slide mounts are typically significantly less expensive than plastic slide mounts. Cardboard slide mounts are generally formed by first and second frame portions which are connected by a hinge. A cardboard spacer is usually glued to an inner surface of the first frame portion so as to create a nest for the film transparency around a central rectangular aperture of the slide mount. With the first and second frame portions open in a butterfly-like position, the film transparency is placed in the film nest. The second frame portion is then folded atop the first frame portion, and the opposing inner surfaces of the first and second frame portions are glued together about all four edges of the slide mount to secure the film transparency therein. This method of loading a film transparency into a cardboard slide mount is typically relatively slow as compared to the previously described method of loading a plastic slide mount.
With the film transparency secured within the slide mount, a photographic image of the film transparency should align with the film windows of the first and second frame portions. Thus, it is important that the film transparency be correctly aligned and secured within the slide mount with the entire photographic image visible through the aperture of the slide mount. In some cardboard slide mounts, however, the film transparency is left unconnected within the film nest so that the photographic image can shift and become partially obscured by the rectangular aperture.
It is also important that the film transparency be capable of adapting to temperature variations occasioned by the intense heat of a light source of a slide projector. In some cardboard slide mounts, the film transparency is secured to the slide mount about all four edges of the film. When such a slide mount is placed in the slide projector""s light source, extreme heat from the light source causes the film to expand and buckle, which in turn causes the projected photographic image to become out of focus.
The present invention is a cardboard-plastic slide mount and a method of forming the same. The cardboard-plastic slide mount includes a cardboard bottom, a plastic middle portion, or brace, and a cardboard cover. The plastic brace gives the slide mount strength and resiliency. The inner surfaces of the bottom and cover are coated with a thin layer of plastic material. This plastic coating provides a smoother surface on the inside of the slide mount, which allows a piece of film transparency to be more easily inserted into the slide mount.
The middle brace is constructed of plastic and is secured to the inner surfaces of the bottom and the cover by bonding the plastic brace to the plastic coating on the cardboard bottom, the cardboard cover, or both using a bonding agent. Creating the slide mount using a bonding agent, rather than glue, reduces or eliminates the cost of glue making the slide mount cheaper to manufacture. In addition, glue may come loose or may react with the film transparency. However, the plastic bonding method used in the present invention creates a more permanent bond and is less reactive, and thus less likely to damage the film transparency.
The brace is bonded to the bottom cardboard on all four sides. The cardboard cover is then affixed to the brace on three sides, leaving an opening through which a piece of film transparency can be inserted. The bottom, brace, and cover each have an opening, or film window. When the brace is secured between the bottom and cover, the film windows of the bottom, cover, and brace are aligned so that a piece of film transparency mounted in the slide mount can be viewed through a central aperture created by the film windows of the bottom, cover, and brace. A secondary adhesive layer may be added to the inner surfaces of the cardboard cover and bottom, so that once inserted, the piece of film transparency is held in place.
When secured between the bottom and cover, the plastic brace creates a film nest between the bottom and cover. The insertion opening communicates with the film nest and allows a piece of film to be inserted through the opening and into the film nest. The secondary adhesive layer can be positioned in the film nest along the film window of the cover so as to hold one edge of the film transparency when the film transparency is positioned in the film nest. The cardboard-plastic slide mount of the present invention is therefore able to be quickly loaded with a piece of film through the insertion opening in a manner similar to plastic slide mounts. Once loaded, the adhesive layer in the film nest secures only one edge of the film transparency, which allows the film transparency to expand without buckling when exposed to the heat of a slide projector""s light source.